governor brown's prop 30 raised taxes. and it hits starting tomorrow. other east bay cities are up in the 9% raise, with bigger cities like san francisco the lowest. steve's tire store is right on the el cerrito-richmond border. >> sales tax right here tomorrow, 9%. >> reporter: the tax from prop 30 will last the next four years. >>> you've been warned. ride the bumper cars at your own risk. >>> and if you get hurt, you can't sue. today the state supreme court ruled a south bay doctor could not sue great america for breaking her risk on the bumper cars. the court said there's a, quote, assumption of risk on such rides. >>> the chp will be looking for anyone who shouldn't be on the roads. and here's a sobering thought. a dui can cost up to $7,000. mark shows us how new technology could put the brakes on drunk drivers. >> so we want to take this device and implement it into the car. >> reporter: bud is leading a research team creating technology that could prevent 10,000 drunk driving deaths a car. unlike this breathalyzer test, these two new sensors woul